This application is based on Japanese Patent Application No. 9-75186, filed Mar. 27, 1997, the contents of which is incorporated herein by reference.
The present invention relates to a display control system used in personal computers and the like and a method for controlling display of three-dimensional graphics data.
Conventionally, a three-dimensional graphics function has been carried out on a workstation mainly for use in engineering such as CAD and CAM. Recently, even in personal computers, the three-dimensional graphics function has been supported for daily use representing entertainment software such as games.
In order to implement a three-dimensional graphics function, generally, not all 3D (three-dimensional) processing (geometry conversion, rendering, etc.) for drawing three-dimensional graphics, is executed by a CPU, but hardware called a 3D graphics accelerator is employed in order to cover part of the 3D operations. If the 3D graphics accelerator is used, a load can be distributed by causing the CPU to execute geometry conversion using floating-point arithmetic and by causing the accelerator to execute rendering including texture mapping and Z buffering, with the result that the 3D graphics can be drawn at high speed.
In recent personal computers, a display screen is improved in resolution and a graphics subsystem, which supports high-resolution display of 800.times.600 dots or 1024.times.768 dots, is the mainstream, whereas the size of a typical screen of 3D graphics is 640.times.480 dots. Thus, a problem poses that if 3D graphics are displayed on the high-resolution display screen, their display size is reduced in appearance.
If 3D graphics are drawn by setting their original screen to a large size of 800.times.600 dots or 1024.times.768 dots in advance, they can be displayed in full on the high-resolution display screen. If, however, the size of the original screen of the 3D graphics is set large in advance, all the 3D operations, such as geometry conversion and rendering necessary for drawing the 3D graphics, is increased in amount. This causes the load of the CPU and the power consumption of the 3D graphics accelerator to increase.
Personal computers are under restrictions on the performance of the CPU and the power consumption of the graphics subsystem and thus excessive processing cannot be executed by the CPU or the 3D graphics accelerator. For this reason, in personal computers, it is practically difficult to set the original screen size of the 3D graphics large before the drawing thereof.
As described above, the personal computers are under restrictions on the performance of the CPU and the power consumption of the graphics subsystem and thus the size of the original screen cannot be set large in advance in accordance with that of a screen on which 3D graphics are to be displayed. It is therefore difficult to display 3D graphics on a screen whose resolution is higher than that of the original screen.